Preparation of luminescent iridium complexes and precursors thereof

ABSTRACT

Synthetic processes for preparing luminescent iridium complexes and precursors thereof are provided. The method employs water as the reaction solvent to prepare luminescent iridium complexes in two different ways. In the first way, a precursor [Ir 2 (C 11 NR 8 ) 4 I 2 ] (Formula I) is prepared from one of IrCl 3 , M 3 IrCl 6  (M=Li, Na, K) and [Ir 2 (C 11 NR 8 ) 4 Cl 2 ], and then the precursor [Ir 2 (C 11 NR 8 ) 4 I 2 ] is converted into one of the two luminescent iridium isomeric complexes [Ir(C 11 NR 8 ) 2 (C 11 NR′ 8 )] (Formula II). In the second way, a metal complex IrCl 3  or M 3 IrCl 6  (M=Li, Na, K), HC 11 NR 8  and a base are converted selectively into one of the two iridium isomeric complexes [Ir(C 11 NR 8 ) 3 ] (Formula VIII). Herein, R and R′ are defined the same as the specification.

CROSS REFERENCE TO RELATED APPLICATION

This application claims the benefits of the Taiwan Patent ApplicationSerial Number 099111329, filed on Apr. 12, 2010, the subject matter ofwhich is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to novel synthetic processes for preparingcomplexes and, more particularly, to novel synthetic processes forpreparing luminescent iridium complexes and precursors thereof.

2. Description of Related Art

In addition to inorganic light emitting diodes (LEDs), organic lightemitting diodes (OLEDs) made of organic materials have attracted a greatdeal of attention for lightening and display applications, and have beenapplied in many products, such as mobile phones, liquid crystaldisplays, flexible displays etc., owing to their low cost, reducedweight, compact volume, low operating voltage and flexibility.

Like conventional inorganic light emitting diodes (LEDs), electrons andholes, formed in OLEDs under electric fields generated by applyingvoltage, will move towards the cathode and the anode, respectively, andthen recombine in an organic layer to form excitons capable ofradiatively relaxing from their excited state to the ground state.

The wavelength of light emitted from OLEDs depends on energy gap betweenHOMO and LUMO of emissive organic materials applied in OLEDs. Compoundscapable of emitting phosphorescent light include transition metalcomplexes, such as osmium complexes, iridium complexes, platinumcomplexes, ruthenium complexes, rhodium complexes etc., which exhibitenhanced luminescence efficiency and have reduced half-life period ofphosphorescence.

Among these transition metal complexes, iridium complexes can show highphosphorescence emission at room temperature, and thetris-cyclometalated iridium complex, fac-[Ir(ppy)₃], is one of the bestgreen phosphorescent materials and can be used as a phosphorescentdopant in an emissive layer of an OLED. Tamayo et al. (Tamayo et al.,2003) published synthesis of fac-[Ir(ppy)₃], in which fac-[Ir(ppy)₃] wassynthesized by reacting [Ir(acac)₃] with 2-phenylpyridine (Hppy) (about3-3.5 equivalents) in an organic solvent by heating under reflux ofglycerol. After using a silica-gel chromatographic column,fac-[Ir(ppy)₃] can be obtained in a yield of 45-60%. In addition,mer-[Ir(ppy)₃] displays similar luminescent behavior to that offac-[Ir(ppy)₃] and can also be used as a phosphorescent dopant in anemissive layer of an OLED. Tamayo et al. (Tamayo et al., 2003) publishedsynthesis of mer-[Ir(ppy)₃], in which mer-[Ir(ppy)₃] was synthesized byreacting [Ir₂(ppy)₄Cl₂] with K₂CO₃ (5-10 equivalents) and2-phenylpyridine (Hppy) (about 2-2.5 equivalents) in an organic solventby heating under reflux of glycerol. After using a silica-gelchromatographic column, mer-[Ir(ppy))] can be obtained in a yield of68-80%.

Therefore, it is desirable to provide easily operated syntheticprocesses for preparing luminescent iridium complexes, fac-[Ir(ppy)₃]and mer-[Ir(ppy)₃], in a satisfactory yield better than 85% withoutusing a chromatographic column for purification.

SUMMARY OF THE INVENTION

The object of the present invention is to provide novel syntheticprocesses for selectively and rapidly preparing iridium complexes inwhich water is used as a reaction solvent. Unlike conventionalsynthesis, no organic solvent is used for the novel synthesis providedby the present invention. Additionally, the novel synthesis provided bythe present invention is advantageous in easy preparation of only one oftwo isomeric products and high yields. Chromatographic separation of anyone pure isomer is hence not needed.

To achieve the object, the present invention provides a novel syntheticprocess for preparing a compound represented by the following formula(II),

including a step of reacting a compound of the following formula (I),and a compound of the following formula (III) in water,

wherein each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷R⁸, R′¹, R′², R′³, R′⁴, R′⁵,R′⁶, R′⁷, and R′⁸, independently, is hydrogen, deuterium, alkyl,alkenyl, alkynyl, halogen, alkoxy, alkenoxy, alkynoxy, haloalkyl,haloalkenyl, haloalkynyl, cycloalkyl, cycloalkenyl or aryl; or R^(x) andR^(x+1) taken together is alkylene, alkenylene, haloalkylene orhaloalkenylene, x being an integer of 1 to 7; or R′^(y) and R′^(y+1)taken together is alkylene, alkenylene, haloalkylene or haloalkenylene,y being an integer of 1 to 7.

Accordingly, the present invention can selectively synthesize the one oftwo luminescent iridium complexes of the formula (II) by the reactionbetween the precursor of the formula (I) and the compound of the formula(III) in water and the obtained product of the formula (II) is either ameridional isomer represented by the following formulas (IV) or a facialisomer represented by the following formula (V) by controlling thereaction temperature,

The present invention further provides a process for preparing theprecursor of the formula (I),

including a step of reacting IrCl₃ or M₃IrCl₆ with MI and a compound ofthe following formula (VI) in water, or reacting a compound of thefollowing formula (VII) with MI in water,

wherein

M is Li, Na or K; and

each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸, independently, is hydrogen,deuterium, halogen, alkyl, alkenyl, alkynyl, alkoxy, alkenoxy, alkynoxy,cycloalkyl, cycloalkenyl or aryl; or R^(x) and R^(x+1) taken together isalkylene alkenylene, haloalkylene or haloalkenylene, x being an integerof 1 to 7.

Accordingly, the present invention can synthesize the precursor of theformula (I) in water and the precursor can be used as a startingmaterial for a next step to synthesize the above-mentioned luminescentiridium complex of the formula (II), as a two-step synthetic process forpreparing luminescent iridium complexes.

In addition, the present invention further provides another novelsynthetic process for selectively preparing a compound represented bythe following formula (VIII),

including a step of reacting IrCl₃ or M₃IrCl₆ with a base and a compoundof the following formula (VI) in water,

wherein

M is Li, Na or K; and

each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸, independently, is hydrogen,deuterium, alkyl, alkenyl, alkynyl, halogen, alkoxy, alkenoxy, alkynoxy,haloalkyl, haloalkenyl, haloalkynyl, cycloalkyl, cycloalkenyl or aryl;or R^(x) and R^(x+1) taken together is alkylene, alkenylene,haloalkylene or haloalkenylene, x being an integer of 1 to 7.

Accordingly, the present invention can selectively synthesize any one oftwo luminescent iridium complexes of the formula (VIII) in water by aone-step process and the obtained product of the formula (VIII) iseither a meridional isomer represented by the following formula (IX) ora facial isomer represented by the following formula (X), by controllingthe amount of the base relative to that of IrCl₃ or M₃IrCl₆,

In the present invention, the base may be any organic base or anyinorganic base.

In the present invention, the term “alkyl” refers to a straight orbranched hydrocarbon. Examples of alkyl include, but are not limited to,methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, and t-butyl.

In the present invention, the term “haloalkyl” refers to alkylsubstituted by one or more halogen atoms. Examples of haloalkyl include,but are not limited to, —CF₃, —CBr₃ and —CCl₃.

In the present invention, the term “alkoxy” refers to —O-alkyl. Examplesof alkoxy include, but are not limited to, —OCH₃, —OCH₂CH₃ and—OCH₂CH₂CH₃.

In the present invention, the term “alkylene” refers to a straight orbranched divalent hydrocarbon. Examples of alkylene include, but are notlimited to, methylene (—CH₂), ethylene (—CH₂CH₂—), and i-propylene(—CHCH₃CH₂—).

In the present invention, the term “haloalkylene” refers to alkylenesubstituted by one or more halogen atoms. Examples of haloalkyleneinclude, but are not limited to, —CF₂—, —CBr₂— and —CCl₂—.

In the present invention, the term “alkenyl” refers to a straight orbranched hydrocarbon containing one or more double bonds. Examples ofalkenyl include, but are not limited to, ethenyl, propenyl, allyl, and1,4-butadienyl.

In the present invention, the term “haloalkenyl” refers to alkenylsubstituted by one or more halogen atoms. Examples of haloalkenylinclude, but are not limited to, —CH₂═CF₂, —CH₂═CBr₂ and —CH₂═CCl₂.

In the present invention, the term “alkenoxy” refers to O-alkenyl.Examples of alkenoxy include, but are not limited to, —OCH₂CH═CH₂,—OCH₂CH₂CH═CH₂ and —OCH₂CH₂CH₂CH═CH₂.

In the present invention, the term “alkenylene” refers to a straight orbranched divalent hydrocarbon containing one or more double bonds.Examples of alkenylene include, but are not limited to, vinylene, andpropenylene.

In the present invention, the term “halo alkenylene” refers toalkenylene substituted by one or more halogen atoms. Examples ofhaloalkenylene include, but are not limited to, —CH₂═CF—, —CH₂═CBr— and—CH₂═CCl—.

In the present invention, the term “alkynyl” refers to a straight orbranched hydrocarbon containing one or more triple bonds. Examples ofalkynyl include, but are not limited to, ethynyl, propynyl and butynyl.

In the present invention, the term “haloalkynyl” refers to alkynylsubstituted by one or more halogen atoms. Examples of haloalkynylinclude, but are not limited to, —C≡CF, —C≡CBr and —C≡CCl.

In the present invention, the term “alkynoxy” refers to O-alkynyl.Examples of alkenoxy include, but are not limited to, —OCH₂C≡CH,—OCH₂CH₂C≡CH and —OCH₂CH₂CH₂C≡CH.

In the present invention, the term “cycloalkyl” refers to a saturatedhydrocarbon ring system, which may be a 5-carbon monocyclic, 10-carbonbicyclic, 14-carbon tricyclic ring system. Examples of cycloalkylinclude, but are not limited to, cyclopropyl, cyclobutyl, cyclopentyl,cycloheptyl, and cyclooctyl.

In the present invention, the term “cycloalkenyl” refers to anon-aromatic hydrocarbon ring system containing one or more doublebonds, which may be a 5-carbon monocyclic, 10-carbon bicyclic, 14-carbontricyclic ring system. Examples of cycloalkenyl include, but are notlimited to, cyclopentenyl and cycloheptenyl.

In the present invention, the term “aryl” refers to an aromatic ringsystem, which may be a 6-carbon monocyclic, 10-carbon bicyclic,14-carbon tricyclic aromatic ring system. Examples of aryl groupsinclude, but are not limited to, phenyl, naphthyl, and anthracenyl.

The above-mentioned alkyl, alkenyl, alkynyl, alkoxy, alkenoxy, alkynoxy,haloalkyl, haloalkenyl, haloalkynyl, cycloalkyl, cycloalkenyl, aryl,alkylene, alkenylene, haloalkylene and haloalkenylene include bothsubstituted and unsubstituted moieties. The term “substituted” refers toone or more substituents (which may be the same or different), eachreplacing a hydrogen atom.

Examples of substituents for alkyl, haloalkyl, alkylene and haloalkyleneinclude, but are not limited to, hydroxyl, amino, alkylamino, arylamino,dialkylamino, diarylamino, cyano, nitro, mercapto, carbonyl, carbamido,carbamyl, carboxyl, thiocyanato, sulfoamido, alkoxy, alkenoxy, alkynoxy,aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl,heterocycloalkenyl, CO₂-alkyl and CO₂-alkenyl.

Examples of substituents for alkenyl, haloalkenyl, alkenylene, andhaloalkenylene include, but are not limited to, hydroxyl, amino,alkylamino, arylamino, dialkylamino, diarylamino, cyano, nitro,mercapto, carbonyl, carbamido, carbamyl, carboxyl, thiocyanato,sulfoamido, alkynyl, alkoxy, alkenoxy, alkynoxy, aryl, heteroaryl,cycloalkyl, cycloalkenyl, heterocycloalkyl, heterocycloalkenyl,CO₂-alkyl and CO₂-alkenyl.

Examples of substituents for alkynyl and haloalkynyl include, but arenot limited to, hydroxyl, amino, alkylamino, arylamino, dialkylamino,diarylamino, cyano, nitro, mercapto, carbonyl, carbamido, carbamyl,carboxyl, thiocyanato, sulfoamido, alkenyl, alkoxy, alkenoxy, alkynoxy,aryl, heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl,heterocycloalkenyl, CO₂-alkyl and CO₂-alkenyl.

Examples of substituents for alkoxy include, but are not limited to,halogen (such as F, Cl, Br or I), hydroxyl, amino, alkylamino,arylamino, dialkylamino, diarylamino, cyano, nitro, mercapto, carbonyl,carbamido, carbamyl, carboxyl, thiocyanato, sulfoamido, alkoxy,alkenoxy, alkynoxy haloalkyl, haloalkenyl, haloalkynyl, aryl,heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl,heterocycloalkenyl, CO₂-alkyl and CO₂-alkenyl.

Examples of substituents for alkenoxy, include, but are not limited to,halogen (such as F, Cl, Br or I), hydroxyl, amino, alkylamino,arylamino, dialkylamino, diarylamino, cyano, nitro, mercapto, carbonyl,carbamido, carbamyl, carboxyl, thiocyanato, sulfoamido, alkynyl, alkoxy,alkenoxy, alkynoxy haloalkyl, haloalkenyl, haloalkynyl, aryl,heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl,heterocycloalkenyl, CO₂-alkyl and CO₂-alkenyl.

Examples of substituents for alkynoxy, include, but are not limited to,halogen (such as F, Cl, Br or I), hydroxyl, amino, alkylamino,arylamino, dialkylamino, diarylamino, cyano, nitro, mercapto, carbonyl,carbamido, carbamyl, carboxyl, thiocyanato, sulfoamido, alkenyl, alkoxy,alkenoxy, alkynoxy haloalkyl, haloalkenyl, haloalkynyl, aryl,heteroaryl, cycloalkyl, cycloalkenyl, heterocycloalkyl,heterocycloalkenyl, CO₂-alkyl and CO₂-alkenyl.

Examples of substituents for cycloalkyl, cycloalkenyl and aryl include,but are not limited to, alkyl, alkenyl, alkynyl, halogen (such as F, Cl,Br or I), hydroxyl, amino, alkylamino, arylamino, dialkylamino,diarylamino, cyano, nitro, mercapto, carbonyl, carbamido, carbamyl,carboxyl, thiocyanato, sulfoamido, alkoxy, alkenoxy, alkynoxy,haloalkyl, haloalkenyl, haloalkynyl, aryl, heteroaryl, cycloalkyl,cycloalkenyl, heterocycloalkyl, heterocycloalkenyl, CO₂-alkyl andCO₂-alkenyl.

Regarding the formulas (I), (II), (III), (IV), (V), (VI), (VII), (VIII),(IX) and (X), preferably, each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R′¹,R′², R′³, R′⁴, R′⁵, R′⁶, R′⁷ and R′⁸, independently, is hydrogen,deuterium, C₁₋₃₀ alkyl, C₂₋₃₀ alkenyl, C₂₋₃₀ alkynyl, halogen, C₁₋₃₀alkoxy, C₂₋₃₀ alkenoxy, C₂₋₃₀ alkynoxy, C₁₋₃₀ haloalkyl, C₂₋₃₀haloalkenyl, C₂₋₃₀ haloalkynyl, C₅₋₁₄ cycloalkyl, C₅₋₁₄ cycloalkenyl orC₆₋₁₄ aryl; or R^(x) and R^(x+1) taken together is C₃₋₁₂ alkylene, C₃₋₁₂alkenylene, C₃₋₁₂ haloalkylene or C₃₋₁₂ haloalkenylene, x being aninteger of 1 to 3 or 5 to 7; or R⁴ and R⁵ taken together is C₁₋₁₀alkylene, C₂₋₁₀ alkenylene, C₁₋₁₀ haloalkylene or C₂₋₁₀ haloalkenylene;or R′^(y) and R′^(y+1) taken together is C₃₋₁₂ alkylene, C₃₋₁₂alkenylene, C₃₋₁₂ haloalkylene or C₃₋₁₂ haloalkenylene, y being aninteger of 1 to 3 or 5 to 7; or R′⁴ and R′⁵ taken together is C₁₋₁₀alkylene, C₂₋₁₀ alkenylene, haloalkylene or C₂₋₁₀ haloalkenylene.

Regarding the formulas (I), (II), (III), (IV), (V), (VI), (VII), (VIII),(IX) and (X), more preferably, each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸,R′¹, R′², R′³, R′⁴, R′⁵, R′⁶, R′⁷ and R′⁸, independently, is hydrogen,deuterium, C₁₋₁₀ alkyl, C₂₋₁₀ alkenyl, C₂₋₁₀ alkynyl, halogen, C₁₋₁₀alkoxy, C₂₋₁₀ alkenoxy, C₂₋₁₀ alkynoxy, C₁₋₁₀ haloalkyl, C₂₋₁₀haloalkenyl, C₂₋₁₀ haloalkynyl, C₅₋₁₀ cycloalkyl, C₅₋₁₀ cycloalkenyl orC₆₋₁₀ aryl; or R^(x) and R^(x+1) taken together is C₃₋₈ alkylene, C₃₋₈alkenylene, C₃₋₈ haloalkylene or C₃₋₈ haloalkenylene, x being an integerof 1 to 3 or 5 to 7; or R⁴ and R⁵ taken together is C₁₋₆ alkylene, C₂₋₆alkenylene, C₁₋₆ haloalkylene or C₂₋₆ haloalkenylene; or R′^(y) andR′^(y+1) taken together is C₃₋₈ alkylene, C₃₋₈ alkenylene, C₃₋₈haloalkylene or C₃₋₈ haloalkenylene, y being an integer of 1 to 3 or 5to 7; or R′⁴ and R′⁵ taken together is C₁₋₆ alkylene, C₂₋₆ alkenylene,C₁₋₆ haloalkylene or C₂₋₆ haloalkenylene.

Regarding the formulas (I), (II), (III), (IV), (V), (VI), (VII), (VIII),(IX) and (X), most preferably,

each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R′¹, R′², R′³, R′⁴, R′⁵, R′6,R′⁷ and R′⁸, independently, is hydrogen; deuterium; halogen;unsubstituted or substituted C₁₋₁₀ alkyl by one or more of C₁₋₁₀ alkoxy,C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy; unsubstituted or substituted C₂₋₁₀alkenyl by one or more of C₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxyand C₂₋₁₀ alkynoxy; unsubstituted or substituted C₂₋₁₀ alkynyl by one ormore of C₂₋₁₀ alkenyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy;unsubstituted or substituted C₁₋₁₀ alkoxy by one or more of halogen,C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy; unsubstituted orsubstituted C₂₋₁₀ alkenoxy by one or more of halogen, C₂₋₁₀ alkynyl,C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy; unsubstituted orsubstituted C₂₋₁₀ alkynoxy by one or more of halogen, C₂₋₁₀ alkenyl,C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy; unsubstituted orsubstituted C₁₋₁₀ haloalkyl by one or more of C₁₋₁₀ alkoxy, C₂₋₁₀alkenoxy and C₂₋₁₀ alkynoxy; unsubstituted or substituted C₂₋₁₀haloalkenyl by one or more of C₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀alkenoxy and C₂₋₁₀ alkynoxy; unsubstituted or substituted C₂₋₁₀haloalkynyl by one or more of C₂₋₁₀ alkenyl, C₁₋₁₀ alkoxy, C₂₋₁₀alkenoxy and C₂₋₁₀ alkynoxy; unsubstituted or substituted C₅₋₁₀cycloalkyl by one or more of halogen, C₁₋₁₀ alkyl, C₂₋₁₀ alkenyl, C₂₋₁₀alkynyl, C₁₋₁₀ haloalkyl, C₂₋₁₀ haloalkenyl, C₂₋₁₀ haloalkynyl, C₁₋₁₀alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy; unsubstituted or substitutedC₅₋₁₀ cycloalkenyl by one or more of halogen, C₁₋₁₀ alkyl, C₂₋₁₀alkenyl, C₂₋₁₀ alkynyl, C₁₋₁₀ haloalkyl, C₂₋₁₀ haloalkenyl, C₂₋₁₀haloalkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy; orunsubstituted or substituted C₆₋₁₀ aryl by one or more of halogen, C₁₋₁₀alkyl, C₂₋₁₀ alkenyl, C₂₋₁₀ alkynyl, C₁₋₁₀ haloalkyl, C₂₋₁₀ haloalkenyl,C₂₋₁₀ haloalkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy; or

R^(x) and R^(x+1) (x being an integer of 1 to 3 or 5 to 7) takentogether is unsubstituted or substituted C₃₋₅ alkylene by one or more ofC₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thusforming a 5-7 membered ring with two carbons bonded to R^(x) andR^(x+1); unsubstituted or substituted C₃₋₅ alkenylene by one or more ofC₂₋₁₀ alkynyl, C₁₋₃ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thusforming a 5-7 membered ring with two carbons bonded to R^(x) andR^(x+1); unsubstituted or substituted C₃₋₅ haloalkylene by one or moreof C₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thusforming a 5-7 membered ring with two carbons bonded to R^(x) andR^(x+1); or unsubstituted or substituted C₃₋₅ haloalkenylene by one ormore of C₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxythus forming a 5-7 membered ring with two carbons bonded to R^(x) andR^(x+1); or

R⁴ and R⁵ taken together is unsubstituted or substituted C₁₋₃ alkyleneby one or more of C₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀alkynoxy thus forming a 5-7 membered ring with two carbons bonded to R⁴and R⁵ and two carbons adjacent to the two carbons bonded to R⁴ and R⁵;unsubstituted or substituted C₂₋₃ alkenylene by one or more of C₂₋₁₀alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thus forming a6-7 membered ring with two carbons bonded to R⁴ and R⁵ and two carbonsadjacent to the two carbons bonded to R⁴ and R⁵; unsubstituted orsubstituted C₁₋₃ haloalkylene by one or more of C₂₋₁₀ alkynyl, C₁₋₁₀alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thus forming a 5-7 memberedring with two carbons bonded to R⁴ and R⁵ and two carbons adjacent tothe two carbons bonded to R⁴ and R⁵; or unsubstituted or substitutedC₂₋₃ haloalkenylene by one or more of C₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀alkenoxy and C₂₋₁₀ alkynoxy thus forming a 6-7 membered ring with twocarbons bonded to R⁴ and R⁵ and two carbons adjacent to the two carbonsbonded to R⁴ and R⁵; or

R′^(y) and R′^(y+1) (y being an integer of 1 to 3 or 5 to 7) takentogether is unsubstituted or substituted C₃₋₅ alkylene by one or more ofC₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thusforming a 5-7 membered ring with two carbons bonded to R′^(y) andR′^(y+1); unsubstituted or substituted C₃₋₅ alkenylene by one or more ofC₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thusforming a 5-7 membered ring with two carbons bonded to R′^(y) andR′^(y+1); unsubstituted or substituted C₃₋₅ haloalkylene by one or moreof C₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thusforming a 5-7 membered ring with two carbons bonded to R′^(y) andR′^(y+1); or unsubstituted or substituted C₃₋₅ haloalkenylene by one ormore of C₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxythus forming a 5-7 membered ring with two carbons bonded to R′^(y) andR′^(y+1); or

R′⁴ and R′⁵ taken together is unsubstituted or substituted C₁₋₃ alkyleneby one or more of C₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀alkynoxy thus forming a 5-7 membered ring with two carbons bonded to R′⁴and R′⁵ and two carbons adjacent to the two carbons bonded to R′⁴ andR′⁵; unsubstituted or substituted C₂₋₃ alkenylene by one or more ofC₂₋₁₀ alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thusforming a 6-7 membered ring with two carbons bonded to R′⁴ and R⁵ andtwo carbons adjacent to the two carbons bonded to R′⁴ and R′⁵;unsubstituted or substituted C₁₋₃ haloalkylene by one or more of C₂₋₁₀alkynyl, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thus forming a5-7 membered ring with two carbons bonded to R′⁴ and R′⁵ and two carbonsadjacent to the two carbons bonded to R′⁴ and R′⁵; or unsubstituted orsubstituted C₂₋₃ haloalkenylene by one or more of C₂₋₁₀ alkynyl, C₁₋₁₀alkoxy, C₂₋₁₀ alkenoxy and C₂₋₁₀ alkynoxy thus forming a 6-7 memberedring with two carbons bonded to R′⁴ and R′⁵ and two carbons adjacent tothe two carbons bonded to R′⁴ and R′⁵.

Examples of the formula (I) include, but are not limited to,

Examples of the formulas (III) and (VI) include, but are not limited to,

Accordingly, the present invention provides a novel one-step or two-stepsynthetic process for selectively preparing luminescent iridiumcomplexes in which water is used as a reaction solvent. Unlikeconventional synthesis, no organic solvent is used for the novelsynthetic synthesis provided by the present invention. Additionally, thenovel synthetic synthesis provided by the present invention isadvantageous in selective preparation of any one of two isomericproducts and high yields.

Other objects, advantages, and novel features of the invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

None

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A better understanding of the present invention may be obtained in lightof the following Examples which are set forth to illustrate, but are notto be construed to limit the present invention.

As a two-step synthesis, precursors of [Ir₂(C₁₁NR₈)₄I₂] were firstprepared from IrCl_(3′)M₃IrCl₆ or complexes of [Ir₂(C₁₁NR₈)₄Cl₂] andthen final luminescent iridium complexes of [Ir(C₁₁NR₈)₂(C₁₁NR′₈)] weresynthesized from the precursors. Herein, the prepared[Ir(C₁₁NR₈)₂(C₁₁NR′₈)] is either fac-[Ir(C₁₁NR₈)₂(C₁₁NR′₈)] ormer-[Ir(C₁₁NR₈)₂(C₁₁NR′₈)] by controlling the reaction temperature.

Synthesis of [Ir₂(ppy)₄I₂]

A precursor of [Ir₂(ppy)₄I₂] was prepared by reacting IrCl₃ or M₃IrCl₆with KI and 2-phenylpyridine (Hppy), or reacting a complex of[Ir₂(ppy)₄Cl₂] with KI as follows. Herein, M is one of Li, Na and K, andppy is 2-phenylpyridyl.

Example 1

IrCl₃ (0.052 g, 0.15 mmole), KI (0.125 g, 0.75 mmole) and2-phenylpyridine (0.1 ml) were placed in a Teflon-lined autoclave, andthen deionized water (10 ml) was added thereto. Subsequently, theautoclave was sealed and heated to perform reaction for 22 hours in anoven at 150° C. Finally, solids collected on a filter paper were washedwith deionized water (30 ml) and recrystallized fromdichloromethane/hexane to obtain a product of 0.083 g in a yield of 88%.

Example 2

An Na₃IrCl₆ aqueous solution containing Na₃IrCl₆ (0.15 mmol) anddeionized water (10 ml) was placed in a Teflon-lined autoclave, and thenKI (0.343 g, 2.07 mmole) and 2-phenylpyridine (0.1 ml) were addedthereto. Subsequently, the autoclave was sealed and heated to performreaction for 24 hours in an oven at 150° C. Finally, solids collected ona filter paper were washed with deionized water (30 ml) andrecrystallized from dichloromethane/hexane to obtain a product of 0.086g in a yield of 91%.

The present example also replaced the Na₃IrCl₆ aqueous solution withother suitable aqueous solutions, such as Li₃IrCl₆ aqueous solution orK₃IrCl₆ aqueous solution, to perform the above-mentioned reaction withKI and 2-phenylpyridine, thus obtaining the product of [Ir₂(ppy)₄I₂].

Example 3

[Ir₂(ppy)₄Cl₂] (0.038 g, 0.035 mmole) and KI (0.583 g, 0.35 mmole, 10equivalents) were placed in a Teflon-lined autoclave, and then deionizedwater (10 ml) was added thereto. Subsequently, the autoclave was sealedand heated to perform reaction for 24 hours in an oven at 150° C.Finally, solids collected on a filter paper were washed with deionizedwater (30 ml) and recrystallized from dichloromethane/hexane to obtain aproduct mixture of [Ir₂(ppy)₄ClI] and [Ir₂(ppy)₄I₂].

The present example also used KI in an amount of 20, 30 or 40equivalents to perform the above-mentioned process, and ratios obtainedfor the unreacted compound, [Ir₂(ppy)₄Cl₂], and two products weredetermined from the integrals of ¹H NMR spectra (Table 1).

TABLE 1 KI (equivs.) [Ir₂(ppy)₄I₂] [Ir₂(ppy)₄Cl₂] [Ir₂(ppy)₄ClI] 100.279% 0.553% 0.168% 20 0.784% 0.085% 0.131% 30 0.188% 0.637% 0.175% 400.045% 0.851% 0.104%

By using various reactants, various products can be synthesized asfollows.

Herein, M is Li, Na or K; and each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸,independently, is hydrogen, deuterium, halogen, alkyl, alkenyl, alkynyl,alkoxy, alkenoxy, alkynoxy, cycloalkyl, cycloalkenyl or aryl; or R^(x)and R^(x+1) taken together is alkylene, alkenylene, haloalkylene orhaloalkenylene, x being an integer of 1 to 7.

Examples of [Ir₂(C₁₁NR₈)₄I₂] include, but are not limited to,

Synthesis of [Ir(ppy)₃]

A luminescent organic complex of [Ir(ppy)₃] can be obtained by reactingthe precursor of [Ir₂(ppy)₄I₂], prepared by Examples 1-3 with2-phenylpyridine. Herein, the prepared [Ir(ppy)₃] is eitherfac-[Ir(ppy)₃] or mer-[Ir(ppy)₃], or one of two isomers in whole or inmajority.

Example 4 Selective Synthesis of mer-[Ir(ppy)₃]

[Ir₂(ppy)₄I₂](0.0740 g, 0.059 mmole) and 2-phenylpyridine (0.08 ml, 0.54mmol) were placed in a Teflon-lined autoclave, and then deionized water(10 ml) was added thereto. Subsequently, the autoclave was sealed andheated to perform reaction for 20 hours in an oven at 150° C. Aftercooling, solids were collected on a filter paper, washed with deionizedwater (50 ml) and recrystallized from dichloromethane/hexane to obtain ayellow product mer-[Ir(ppy)₃] of 0.0672 g in a yield of 87%.

Example 5 Selective Synthesis of fac-[Ir(ppy)₃]

[Ir₂(ppy)₄I₂] (0.0623 g, 0.050 mmole) and 2-phenylpyridine (0.08 ml,0.54 mmol) were placed in a Teflon-lined autoclave, and then deionizedwater (10 ml) was added thereto. Subsequently, the autoclave was sealedand heated to perform reaction for 24 hours in an oven at 200° C. Aftercooling, solids were collected on a filter paper, washed with deionizedwater (50 ml) and recrystallized from dichloromethane/hexane to obtain ayellow product fac-[Ir(ppy)₃] of 0.0576 g in a yield of 88%.

Example 6 Selective Synthesis of fac-[Ir(tpy)₃]

[Ir₂(tpy)₄I₂] (0.0326 g, 0.025 mmole) and Htpy (0.0110 g, 0.06 mmole)were placed in a Teflon-lined autoclave, and then deionized water (10ml) was added thereto. Subsequently, the autoclave was sealed and heatedto perform reaction for 24 hours in an oven at 150° C. After cooling,solids were collected on a filter paper, washed with deionized water (50ml) and recrystallized from dichloromethane/hexane to obtain a yellowproduct fac-[Ir(tpy)₃] of 0.0311 g in a yield of 89%.

By using various reactants, various products can be synthesized asfollows.

Herein, each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷, R⁸, R′¹, R′², R′³, R′⁴, R′⁵,R′⁶, R′⁷ and R′⁸, independently, is hydrogen, deuterium, alkyl, alkenyl,alkynyl, halogen, alkoxy, alkenoxy, alkynoxy, haloalkyl, haloalkenyl,haloalkynyl, cycloalkyl, cycloalkenyl or aryl; or R^(x) and R^(x+1)taken together is alkylene, alkenylene, haloalkylene or haloalkenylene,x being an integer of 1 to 7; or R′^(y) and R′^(y+1) taken together isalkylene, alkenylene, haloalkylene or haloalkenylene, y being an integerof 1 to 7.

As an one-step synthesis, any one of the two luminescent iridiumisomeric complexes of [Ir(C₁₁NR₈)₃] can be selectively prepared from acomplex of IrCl₃ or M₃IrCl₆ (M is Li, Na or K) with HC₁₁NR₈ in thepresence of a base. Herein, the prepared [Ir(C₁₁NR₈)₃] is eitherfac-[Ir(C₁₁NR₈)₃] or mer-[Ir(C₁₁NR₈)₃] by controlling the amount of thebase relative to that of IrCl₃ or M₃IrCl₆ as follows.

Example 7 Selective Synthesis of mer-[Ir(ppy)₃] by Using an Organic Base

IrCl₃ (24.1 mg, 0.068 mmole), 2-phenylpyridine (33.9 mg, 0.212 mmole)and Ph₂NH (86.2 mg, 0.415 mmole) were placed in a Teflon-linedautoclave, and then deionized water (10 ml) was added thereto.Subsequently, the autoclave was sealed and heated to perform reactionfor 24 hours in an oven at 200° C. After cooling, filtration wasperformed via a filter funnel, and collected solids are washed withlarge amount of water, and then recrystallized fromdichloromethane/hexane. Yellow powder of 0.039 g in a yield of 87% wasobtained after drying.

Example 8 Selective Synthesis of fac-[Ir(ppy)₃] by Using an Organic Base

IrCl₃ (22.5 mg, 0.064 mmole), 2-phenylpyridine (31.6 mg, 0.200 mmole)and Ph₂NH (39.8 mg, 0.192 mmol) were placed in a Teflon-lined autoclave,and then deionized water (10 ml) was added thereto. Subsequently, theautoclave was sealed and heated to perform reaction for 48 hours in anoven at 200° C. After cooling, filtration was performed via a filterfunnel, and collected solids were washed with large amount of water andthen recrystallized from dichloromethane/hexane. Yellow powder of 0.0361g in a yield of 86% was obtained after drying.

Example 9 Selective Synthesis of fac-[Ir(ppy)₃] by Using an InorganicBase

IrCl₃ (22.5 mg, 0.064 mmole), 2-phenylpyridine (31.5 mg, 0.212 mmole)and Na₂CO₃ (10.4 mg, 0.098 mmole) were placed in a Teflon-linedautoclave, and then deionized water (10 ml) was added thereto.Subsequently, the autoclave was sealed and heated to perform reactionfor 48 hours in an oven at 200° C. After cooling, filtration wasperformed via a filter funnel, and collected solids were washed withlarge amount of water and then recrystallized fromdichloromethane/hexane. Yellow powder of 0.0373 g in a yield of 89% wasobtained after drying.

Example 10 Selective Synthesis of mer-[Ir(ppy)₃] by Using an InorganicBase

IrCl₃ (23.3 mg, 0.066 mmole), 2-phenylpyridine (33.6 mg, 0.212 mmole)and Na₂CO₃ (21.0 mg, 0.198 mmole) were placed in a Teflon-linedautoclave, and then deionized water (10 ml) was added thereto.Subsequently, the autoclave was sealed and heated to perform reactionfor 24 hours in an oven at 150° C. After cooling, filtration wasperformed via a filter funnel, and collected solids were washed withlarge amount of water and recrystallized from dichloromethane/hexane.Yellow powder of 0.0375 g in a yield of 87% was obtained after drying.

The iridium complexes, fac-[Ir(C₁₁NR₈)₃] or mer-[Ir(C₁₁NR₈)₃], can beselectively prepared from a complex of IrCl₃ or M₃IrCl₆ (M is Li, Na orK) by controlling the amount of the added base relative to that of IrCl₃or M₃IrCl₆ as follows.

Herein, M is Na, Li or K; and each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷R⁸,independently, is hydrogen, deuterium, halogen, alkyl, alkenyl, alkynyl,alkoxy, alkenoxy, alkynoxy, cycloalkyl, cycloalkenyl or aryl; or R^(x)and R^(x+1) taken together is alkylene alkenylene, haloalkylene orhaloalkenylene, x being an integer of 1 to 7.

Although the present invention has been explained in relation to itspreferred embodiment, it is to be understood that many other possiblemodifications and variations can be made without departing from thespirit and scope of the invention as hereinafter claimed.

What is claimed is:
 1. A method for preparing a compound represented bythe following formula (VIII),

wherein the compound of the formula (VIII) is either a meridional isomerrepresented by the following formula (IX) or a facial isomer representedby the following formula (X),

including a step of reacting IrCl₃ or M₃IrCl₆ with a base and a compoundof the following formula (VI) in water,

wherein M is Li, Na or K; and each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸,independently, is hydrogen, deuterium, alkyl, alkenyl, alkynyl, halogen,alkoxy, alkenoxy, alkynoxy, haloalkyl, haloalkenyl, haloalkynyl,cycloalkyl, cycloalkenyl or aryl; or R^(x) and R^(x+1) taken together isalkylene, alkenylene, haloalkylene or haloalkenylene, x being an integerof 1 to
 7. 2. The method as claimed in claim 1, wherein each of R¹, R²,R³, R⁴, R⁵, R⁶, R⁷ and R⁸, independently, is hydrogen, deuterium, C₁₋₃₀alkyl, C₂₋₃₀ alkenyl, C₂₋₃₀ alkynyl, halogen, C₁₋₃₀ alkoxy, C₂₋₃₀alkenoxy, C₂₋₃₀ alkynoxy, C₁₋₃₀ haloalkyl, C₂₋₃₀ haloalkenyl, C₂₋₃₀haloalkynyl, C₅₋₁₄ cycloalkyl, C₅₋₁₄ cycloalkenyl or C₆₋₁₄ aryl; orR^(x) and R^(x+1) taken together is C₃₋₁₂ alkylene, C₃₋₁₂ alkenylene,C₃₋₁₂ haloalkylene or C₃₋₁₂ haloalkenylene, x being an integer of 1 to 3or 5 to 7; or R⁴ and R⁵ taken together is C₁₋₁₀ alkylene, C₂₋₁₀alkenylene, C₁₋₁₀ haloalkylene or C₂₋₁₀ haloalkenylene.
 3. The method asclaimed in claim 1, wherein each of R¹, R², R³, R⁴, R⁵, R⁶, R⁷ and R⁸,independently, is hydrogen, deuterium, C₁₋₁₀ alkyl, C₂₋₁₀ alkenyl, C₂₋₁₀alkynyl, halogen, C₁₋₁₀ alkoxy, C₂₋₁₀ alkenoxy, C₂₋₁₀ alkynoxy, C₁₋₁₀haloalkyl, C₂₋₁₀ haloalkenyl, C₂₋₁₀ haloalkynyl, C₅₋₁₀ cycloalkyl, C₅₋₁₀cycloalkenyl or C₆₋₁₀ aryl; or R^(x) and R^(x+1) taken together is C₃₋₈alkylene, C₃₋₈ alkenylene, C₃₋₈ haloalkylene or C₃₋₈ haloalkenylene, xbeing an integer of 1 to 3 or 5 to 7; or R⁴ and R⁵ taken together isC₁₋₆ alkylene, C₂₋₆ alkenylene, C₁₋₆ haloalkylene or C₂₋₆haloalkenylene.
 4. The method as claimed as claim 1, wherein the base isan organic base or an inorganic base.
 5. The method as claimed as claim1, wherein the compound of the formula (VI) is


6. The method as claimed as claim 1, wherein the base is Na₂CO₃.
 7. Themethod as claimed as claim 1, wherein the base is Ph₂NH.
 8. The methodas claimed as claim 6, wherein the compound of the formula (VIII) is ameridional isomer represented by the following formula (IX) when theamount of Na₂CO₃ is 1.5 equivalents relative to that of IrCl₃ or M₃IrCl₆or a facial isomer represented by the following formula (X) when theamount of Na₂CO₃ is 3 equivalents relative to that of IrCl₃ or M₃IrCl₆,


9. The method as claimed as claim 7, wherein the compound of the formula(VIII) is a meridional isomer represented by the following formula (IX)when the amount of Ph₂NH is 3 equivalents relative to that of IrCl₃ orM₃IrCl₆ or a facial isomer represented by the following formula (X) whenthe amount of Ph₂NH is 5 equivalents relative to that of IrCl₃ orM₃IrCl₆,